Electrical condenser



June 28,- 1932. w H. FRIES S ELECTRICAL CONDENSER Original Filed Jan. 6. 1922 ATTORNEY Patented June 1932 UNITED STATES PATENT OFFICE WILLIAM 3. 3931158, UPPER HONTGIrAIR, NEW JERSEY, ASSIGNOR, BY HESNE .AS- SIGNHENTS, TO GENERAL ELECTRIC COMPANY, A CORPORATION 01' NEW YORK amc'rmcar. commnsxn Original application liled January 6, 1982, Serial No. 527,449. Divided and this application fled April 27, 1998 Serial No. 104,881.

This ap lication is a division of my application rial No. 527,449, filed January 6, 1922.

This invention relates to electrical con- 5 densers;

The condensers of the present invention, of which several forms are illustrated and described, are of general application or use.

By way of example, they are adapted for 1 use as series antenna condensers, grid condensers, key condensers, bypass condensers, dummy circuit condensers and receiving circuit condensers, for amateur or commercial use in radio communication.

The condenser of this invention comprises a stack com osed of alternate sheets'of armatures an dielectric, the armatures comprising foil preferably of lead, tin or copper, and the dielectric being preferably of mlca,

v with the sheets of foil and dielectric in intimate contact or substantially so, and pref,-

erably treated with wax or some other insulating material.

An object of the invention is to provide a low cost, compact condenser of high eificiency. I

Another object of the invention is to provide a construction of series sectional stack in which the leads may be brought out at opposite ends, irespective of the number of sections, and even when there is an even number of sections.

Of the drawing,

Fig. 1 is a diagrammatic expanded view of a condenser stack, illustrating the arrangement of sheets of dielectric and foil and their connections;

Fig. 2 is a diagrammatic expanded view of another form of condenser stack embodying the arrangement of Fig. 1 and Figc 3 is a diagrammatic illustration of a series-sectional stack having an even number of single sections, as in the prior art, showing how the leads come out therein at the same end: and i Fig. 4 is a plan of the so-called double section of Figs. 1 or 2; and

Fi 5 an elevation of the condenser stack of Figs. 1 or 2, completed, clamped, and encased ready for service.

it impossible, using the type of series section the stack comprises an even number of see- (Figs. 1-2 being expanded), my invention the prior art.

have

In the type of condenser herein illustrated and described, in which the stack as a whole must be electrically divided into sections connected in series for desired potential, I found Ill stack now in use, (Fig. 3), to bring the terminal leads out from opposite sides of the stack unless the series-sectional stack consisted of an odd number of sections. Where tions each constructed in the usual manner and connected in series as illustrated in Fig. 3, the leads must be brought out IIQlIl'thQ same side of the stack, on o posite sides of insulating separator 13. Obviously, where there are an odd number of sections the terminal leads may be brou ht out from opposite sides of the stack. In li igs. 1, 2 and 4, however I have illustrated diagrammatically, m whereby it is practicable to bring the terminal leads from'opposite ends of the stack, even where the stack consists of an even number of sections connected in series. Referring to Fig. 1, I have illustrated a stack comrisin one section D which I have called a doub e section to distinguish it from the single section of the type of condenser section now well known, as used as in Fig. 3 in Referring to Fig. 2, the stack comprises several sections A, B, C connected in series, these sections being of proper number, size and area forthe required capacity and voltage. As here illustrated, the intermediate section B, a double section like section D, Fig. 1, comprises in effect two condensers connected in series but having integral series connections with each other, certain of the foil 'orarmature sheets of this double section formingintegral series connections between the two electricall distinct portions of the double section. or this purpose, I

provided a number of sheets of dielectric 1 (referring to section D, Fig. 1, for simplicity) on one side of each of which is a pair of foils 2 (Fig. 4) in the sameplane and spaced apart from each other at their adjacent edges at 3 Fig. 1, and having their remote edges projecting as terminal leads beyond opposite ends of adjacent dielec' tries 1. Upon the other face of each dielec-' trio 1 is a single sheet of foil 4 (Figs. 1 and 4) which is arranged (Fig. 1) centrally of the sheets of dielectric 1, being spaced 1nwardly from all edges thereof, i. e., not projecting out beyond the dielectrics, and therefore constituting what is termed a floating armature. This foil 4 also is disposedcentraly of the pair of spaced foils 2, buton the other face of the same dielectrical sheet 1; and,'as will be seen later, the central parts of all foils 4 (i. e., the parts bridging foils, 2, 2 on the opposite face of dielectric 1) constitute the series connection between the two electrical sections of this double section. The pairs of spaced but projecting foils 2 alternate with foils 4, a dielectric sheet 1 lying between each floating foil 4 anda pair of foils 2. The non-projecting foils 4 also form common opposing armatures for the pairs of spaced projecting foils 2,forming therewith in effect two condensers connected in series, all the short foils 2 at the left electrically constituting one condenser and all of them at the right electrically constituting the other condenser. That is to say, there is a foil 4 between two adjacent sheets of dielectric, and there are pairs of edge-spaced foils 2 upon the opposite surfaces of said adjacent dielectrics, each foil 4 constituting a common opposing armature for each pair of foils 2, and all the foils 4 also serving as a series connection between the two condensers formed by foils 4 respectively with the two sets of foils 2. Figs. 1 and 2, it is to be understood, show expanded views of the stacks, and in actual construction the thickness of the stack would be very much less and such as to fit in suitable clamp C and easing E indicated in Fig. 5, the sheets of foil and dielectric being com ressed into close contact with each other for est operation.

In finishing the double section D (Fig. 1) after its assembly, the portions of the foils 2 which project from one sideof the stack are soldered together and the portions of the other foils 2 which project from the opposite side of the stack are soldered to- -gether, as illustrated diagrammatically by the lines 5 connecting stack foils in Figs. 1

- and 2, thereby forming two opposite terminal leads 5 connected to terminals 10, 11 of Figs. 1 and 5. In order to strengthen the soldered leads 5, the outer foil elements (marked X) at the end of each double section may be of metal havin greater strength than the innor stack-fol s, intermediate the stack ends. For example, such inner foil elements 2 may consist of rather fragile lead foil, while the outer or end elements X may consist of copper foil or a heavier lead foil, which, when soldered together, prevents the tearing of the foil projections or terminals 5, as by mechanical stresses from the terminals 10, 11.

In order to understand the significance of the above arrangement of theparts' 1, 2 and 4, consider a portion of Fig. 1, i. e., the top pair of'foils 2, the mica dielectric 1 below them, the floating foil 4 below that, the next lower dielectric 1 and the next lower pair of foils 2. One of the two elemental electrostatic condensers of this double condenser section comprises the two left hand foils 2 one above the other, with the left portion of longer foil 4 and the left portions of the two mica sheets .1, 1; and the other elemental condenser com rises the two right hand foils 2 one above t e other in Fig.1 with the right handportion of longer foil 4 and the right hand portions of the two mica sheets 1, l and the integral connection between the right and left halves of intervening longer and float.- ing foil 4 constitutes the series connection between said two elemental condensers. By virtue of this construction, a special or double condenser'section (D) is made suitable for incorporation as at B, Fig. 2, with ordinary sections A, C of a series sectional condenser.

This double'section (D, Fig. 1 and B, Fig. 2) is, inelectrostatic effect the same as two ordinary sections connected in series, i. e., the same in effect as sections A and C in Fig. 2 if they were connected directly in series with one another b conductors exterior of the stack without ouble section B itself. Hence ina four-section stack (electrostatically) as in Fig. 2, this double section takes the place "of two separate sections like sections A and C and additional to A and C, so far as the electrostatic effect is concerned. But if the stack consisted of four separate sections like A and C, (or any even number of such sections) the terminal leads would have to be brought out from the same side of the seriessectional stack (Fig. 3) that being due to the facts 1) that the terminal leads from each such separate sections are brought out from the two opposite sides of such section, (2) that the two adjacent terminal leads of two adjacent separate sections are connected together'in order to constitute the series-sectional condenser stack, and (3) that the other two terminal leads of such two adjacent sections are brought out on the same side of the stack of serially connected sections; so that in the case of a series-sectional .stack of four or any other even number of sections, the two terminals of the stack, (i. e. those of high po: tential difference at opposite end sections of the stack), are at the same side of the stack. The. object of the invention, however, is to. provide a stack of serially connected sections wherein the oppositely poled stack-end terminal leads will extend from opposite sides of the stack, (especially when the number of sections is small and therefore the stack-end terminal leads of hi 'h potential difference will lie close together? and that object is atone or more double sections tained by using double section B of 2 as one or more of the stack-sections which are separated from one or more adjacent sections by such an insulating se arator as 13, and which are connected in series with one or more adjacent sections by such a stack-exterior connector as 6 or 7. And that object is attained by reason of the fact that double section.B, altho electrostatically. equivalent to two ordinary sections like A and C, yet differs from two prior adjacent separate sections (Fig. 3) in that it has onl two external terminal leads, and those eing on opposite ends of the assembly of condenser sheets, just as in the case of an ordinary section as A or C, Fig. 2. The reason why those leads (of the electrostatically double section) can be so brought out is to be found in the abovedescribed construction of the double section itself. But the reason, more important in the invention, why a series-sectional stack having like section B, can have its two stack-terminal leads extend out from the same side of the stack, is that such electrostatically double section has, on its opposite sides, only two external terminal leads, so that so far as concerns the terminal leads and their connections to one another outside they stack to constitute the series-sectional stack", the situation is as if there were one less section (like Am C) in the stack. Thus, as in Fig. 2, altho, electrostatically, the stack comprises four sections, i. e., A, C and the two of double section B, yet it comprises only three sections, mechanically of which each has external terminal leads at opposite sides. In Fig. 2, if double section B were replaced by two single sections like A and C, (making four or an even number of ordinary separate sections) then the exterior stackterminals 8 and 9 necessarily would lie on the same side of the stack as in the case of the even-number-section prior-art stack of Fig. 3. But owing to the fact that double section B has only twio external terminal-leads 5. 5, (by which it is connected at 6 and 7 in series with single. sections A and C), the series connection system of the stack-sections is such that the number of exterior series connections (6 and 7) is even. This has an efi'ect which will be seen more clearly after the following detailed description of Fig. 2.

In Fig. 2, sin le sections A and C are connected at 6 and Z in series with a double sec tion B, (like D, Fig. 1) the single sections A, C being located on opposite sides of the double section B. The three sections are connected in series, via foils 2, at 6 and 7, i. e., alternately at opposite sides of the entire stack, as usual. But altho the sections are (in an electrostatic sense) even in number (four in all, including the two in double section B), yet on account ofjthe novel nature' of double section B, the terminal leads 8 and 9 are permitted to be brought out from opposite sides of the stack of three sections, as 1n Flg. 5 (oppositely'poled terminals 10, 11) and as dlsti-nguished from Fig. 3 where the oppositely poled terminals must be'brought. out at the same side of the stack. ,Interposed' between the sections A, B and C are insulatmg section separators 13, preferably of some cheap insulating material such as fish paper,

or even the more expensive mica, which, when the'condenser stack is assembled and soldered, will pro ect beyond these sections as usual in series sectional condensers. The path of the condenser action through the double section B (Fig. 2) or D (Fig.1) is through one group of spaced foils 2, (all those, say, at the left), through the dielectrics 1' to the floating foils 4, along thelength of the latter and through the same dielectrics again to the second group of foils .2, i. e., all those, say, at the right; that is, the action traverses the dielectrics twice in going from one terminal lead 5 to the other. 1

Thus the series connectors (6, 7) between the end sections are even in number, so. that the system is as follows. One stack-end terminal lead at 8 being at, say (Fig. 2) the right-hand side of section A, the first exterior connection 6 leads from the left of that section, around insulating separator 13 to the left of section B. (The number of exterior series connections for the stack of an even number of sections is prevented from being an odd number'because one exterior series connection is permitted to be omitted by virtue of the fact that the two sections 'electrostatically existing in double section B are connected together inside section B by way of armatures 4). The second exterior connection 7 leads from the right-hand side "of section B (just as if that section were a single section like A), around second insulator 13 to the right of section C. The other terminal lead of section C of course isat its left side; and since this section is the end sec tion of the stack, its terminal lead 9 is the stack terminal lead. And, owing to the pres-. ence of double section B, the second stackterminal' lead 9 is at the opposite side of the stack from its first terminal lead 8.

The terminals, such as Sand 9 (Fig. 2) or 10 and 11 (Fig. 1), comprise preferably stranded copper wire, (Fig. 5) that is, a composite conductor made up of very small wires stranded together but flared apart at the end (Y), Fig. 5, which is to be soldered to a projecting foil bunch, thereby providing a multioint attachment of terminal to foilbunch, t at is, ah attachment in which a number of very small flexible wires are soldered near their ends to the foil bunch projecting from an end section'of the stack 01' from the double section alone of Fig. 1. This construction provides a very strong and permanent electrical connection between the foil bunches and the termina1s 8--9 or.1011,

section illustrated in Fig. 1, while providing, in effect, two condensers connected in series, allows the terminals 10 and 11 to be brought out at opposite sides of the stack. (Contrast Fig. 3.) The construction illustrated in Fig. 2, while providing electrostatically four condensers connected in series by way of leads 6 and 7 and by the foils 4 inside the double section, (and heretofore requiring the terminal leads to be brought out at the same side of the stack), also allows the terminals to be brought out at opposite sides of the stack. Where the number of electrostatic condensers or sections connected in series required is an odd number, electrostatically single sections like A or C may be used exclusively, as in the prior art, altho not necessarily, for a stack might consist of only sections A and B of Fig. 2 without the advantage of having the stack terminal leads at opposite sides of the stack. In any embodiment of the invention, for even numbers of electrostatic sections connected in series, either an odd number of double sections D, Fig. 1, may be used, as by stacking together an even number of double sections like D of Fig. 1, with insulating separators 13 between them as in Fig. 2, so as to cause the stack-terminals from the ends sections to extend from opposite sides of the stack; or an odd number of doublesections with an even number of single sections may be stacked, as illustrated in Fig. 2 with the same result of stack-terminals from opposite sides of the stack-ends. As another example, for a stack having six electrostatic condensers or sections in series, there may be used either three double sections like D of Fig. 1, (with separators 13 and series connectors 6, 7 as in Fig. 2).0r one of such double sections and four single sections like A or C of Fig. 2 with the usual separators 13 and connectors 6, 7 For a stack having eight sections or condensers connected in series, three double sections and two single sections may be used,

or one double section and six single sections, in any case for the purpose of permitting the terminals to be brought out from opposite sides of the stack. Of course, a double section need not be located between single sections as shown in Fig. 2, but may be located at the end of the condenser.

The form of double section illustrated in Fig. 1 at D and in Fig. 2 at B, besides being capable of use for bringing the stack leads out at opposite sides of the stack of Fig. 2 and thereby lessening the insulation diificulties, obviates the necessity of soldering together the foil armatures of the two sections 'of a double section, and of providing a space for this soldering; the connections in this case being integral with their connected foil armatures and no sectional separator 13 being necessary inside the novel. double sections. The double section type herein disclosed (Figs. 1, 2 and 4) has greater strength foilterminals or tabs, (where the bunch of foils 2 are soldered together at 5 to which bunch the terminals 10 and 11 are connected), than a two-single sectional form of the prior art as illustrated in Fig. 3; because, for a stack of the same capacity and number of dielectrics, a larger number of foils 2 are employed in Figs. 1, 2 and 4 which are soldered together in a foil bunch.

The condenser double sections such as illustrated diagrammatically in Figs. 1 and 2 are built up preferablyas are single sections A and C of Fig. 2, i. e. by stacking the foils and dielectric 1 in their previously dipping the dielectric, which is preferably of mica, in melted or liquid insulating material such as parafiin or by building the stack in such melted or liquid insulating material. The stack unit or section is then placed in a pressing stand and heated in a bath of molten paraifin at a temperature of approximately150 C. for about twenty minutes, removed from the bath and cooled under a pressure of the order of 600 pounds. The double section or stack should then be tested for breakdown and measured for capacity, just as in the case of a single section. In Fig. 2, where the single sections are combined with the double sections, all the physically separated sections are connected together in series by soldering together the foil-bunches at 6 and 7, the permanent insulating separators 13 being inserted between each pair of physically separate sections. The stack of sections is then secured in its clamp or casing, or both, which may be of any desired construction as clamp C in'casing E in Fig. 5.

Here is provided a series sectional stack under practical operating conditions of clamping and encasement and consisting of an even number of sections, physically separate from one another but in which the terminals (10, 11, Fig. 5) may be and are brought out-at opposite ends of the condenser as a whole, and directly connected to terminal leads 8. 9 of Fig. 2 brought out from opposite sides of the condenser terminals 10, 11 are insulated from casing E and from each other by means of the mica end pieces 58, 59 and insulating bushings 56 at the open ends of the casing, and by the insulating sheets 44 (as mica) projecting beyond the stack and the clamp C, and around the soldered connections be- (twice as many) proper order, preferably tween the projecting stack-foils and the flared (Y) bared ends of the insulated stranded terminals 10,11. It is by means of a double section shown in Fig. 1 at D and in Fig. '2 at B that it is made possible to bring out the two terminals at opposite portions of the stack and condenser, when there are two sections (or any even number) in the stack; all as contrasted with the prior art in Fig. 3.

In addition to the matter of bringing out the stack-terminals from opposite sides of the series sectional stack, adapting the latter to use with clamp and/or casing of Fig. 5, whether the number of electrostatic sections is odd or even, the advantages of the invention include the very desirable feature of stronger soldered projecting foil-bunches, and (in each double section) the provision of series connections inside the stack thereby eliminating outside foil connections between the two electrical sections of double sections, certain foils however (2, 2) projecting outside the stack to provide exterior foil leads permitting attachment of condenser terminals or permitting soldering into series connection with other and adjacent sections of a seriessectional stack as in Fig. 2.

I claim 1. An improved stack-sheet condenser of the general series-sectional type and including electrostatically double and single sections in a stack including insulating separators between adjacentphysical sections, .said stack including electrostatically single sec- 35 tions and a number of electrostatically double sections sufiicient to constitute an even number of electrostatic sections, an even number of insulating section-separators, and an odd number of physical sections.

2, An improved stack-sheet condenser of the general series-sectional type and including an odd number of physical sections connected in series with one another and one less insulating separators respectively between adjacent physical sections, said odd number of sections including an odd number of electrostatically double sections and an even num-i ber of electrostatically single sections and an I even number of insulating section-separators each of all the sections having its oppositelypoled armatures projecting as section-terminals from opposite sides of the stack, and the provision of the odd total number of physical sections causing the proj ecting-armature terminals of the end sections of the stack to project from opposite sides of the stack.

3. An improved stack-sheet condenser of the general series-sectional type and including an even number of electrostatic sections,

at least four, connected in series, said even number of electrostatic sections being distributed between an odd number of physical sections in the stack, in number less than'the number of electrostatic sections; at least two 0 of the electrostatic sections being consolidated in a single physical section wherein the .two electrostatic sections are connected in series by connecting means inside the double sectionjinsulating separators between adjacent physical sections; and series connection between adjacent physical sections consisting of projecting armature sheets from the same sides of the adjacent externally of the stack around the insulating separators. j

4. An improved stacked-sheet condenser of the general series-sectional type wherein adjacent sections are isolated electrostatically from one another by insulating sheets thicker than the dielectric sheets and placed between i and electrostatically separating the adjacent sections, said sections being connected together electrically by way of connections of their projecting armature sheets extending around the insulating separators, in which type a stack comprising an even number of sections and extending sections includes an odd number of insulating separators and the armatures projecting as stack-terminals from the end sections of the stack naturally extend from the same side of the stack, said improved condenser having an even number of at least four electrostatic sections and of insulating separators, and projecting armatures extending as stack-terminals from the end sections of the stack from opposite sides of the stack by virtue of the inclusion in the stack of at least one electrostatically double section having oppositelypoled armaturcs'projecting as section-terminals from opposite sides of the stack, said projecting armatures including two separate edge-spaced armature sheets on one face of a iven dielectric sheet but respectively projecting from opposite sides of the double section and the stack, and said double section including a relatively large armature sheet on the opposite face of said given dielectric sheet, and inwardly spaced from all the edges of said dielectric sheetbut overlapping said two relatively small spaced armature sheets on the first face of said dielectric sheet.

5. An improved stacked-sheet condenser of the general series-sectional type wherein adjacent sections are isolated electrostatically from one another by insulating sheets thicker than dielectric sheets and placed between and electrostatically separating the adjacent sections, said sections being connected together by 'way of connections of their projecting armature sheets extending around the insulating separators, in which type a stack comprising an even number of sections includes an odd number of insulating separators, and the armatures projectin as stack-terminals from the end sections 0 the stack naturally extend from the same side of the stack, said improved condenser having an even number of atleast four electrostatlc sections and of stack as section-terminals by virtue of the inclusion in the stack of at least one electrostatically double section having oppositely poled armatures projecting from opposite sides of the double section as section-terminals by virtue of electrical connections inside the double section between the two electrostatic portions thereof.

6. An improved stack-sheet condenser of 10 the general series-sectional type, said condenser having an even number of electrostatic section's, an even number of insulating separators respectively between adjacent sections and projecting armatures extendin from end sections of the stack as stack-terminals from opposite side of the stack by virtue of the inclusion in the stack of at least one electrostatically double section having only two proi'ecting-armature terminals which respectivey project from opposite sides of the electrostatically double section.

7 A series-sectional condenser stack which includes at least two successively adjacent physical sections constituting an even numher of electrostatic sections, an insulating separator between and isolating adjacent physical sections electrostatically from one another, and series connections between adjacent physical connections constituted by connected armature-projections respectively extending exteriorly of the stack from the adj acent sections and lying on the same side of the stack and extending around the insulating separator; at least one of the physical sections so isolated and so connected to an adjacent physical section on the stack, being constituted by an electrostatically double section V of which the two portions are connected in series electrically in the interior of the double section itself.

A series-sectional condenser stack including at least two physically separate sections of which at least one is an electrostatically double section of which the twoelectrostatic portions are connected together in series with one another by way of armatures in the interior of such double section.

In testimony whereof I hereunto afiix my signature.

, WILLIAM H. PRIESS. 

